US1481376A

US1481376A - Trailer traction hitch

Info

Publication number: US1481376A
Application number: US561879A
Authority: US
Inventors: John H Klein
Original assignee: Individual
Current assignee: Individual
Priority date: 1922-05-18
Filing date: 1922-05-18
Publication date: 1924-01-22
Anticipated expiration: 1941-01-22

Description

Jan. 22 1924. 1,481,376

J. H. KLEIN TRAILER TRACTION HITCH Filed May 18. 1922 @301 we q Patented Jan. 22, 1924.

UNITED STATES PATENT OFFICE.

JOHN H. KLEIN, OF DENVER, CGIIORADO.

TRAILER rnac'rron' Erma.

Application filed Kay 18, 1922. Serial No. 501,879.

Q0 orado; have invented certain new and useful Improvements in Trailer Traction Hitches; and I .do declare the following to be a full, clear, and exact description of the invention such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

This invention relates to a means for hitching a trailer to a tractor so that the force required to pull the latter will be partly resolved into a vertical component, which will tend to force the rear or traction wheels against the roadbed so as to secure the required traction.

In late years interurban transportation by means of trucks has become extensively employed for short hauls and has proven to be both more economical and quicker than railroad transportation. In order to conserve the highways, it has become necessary to limit the load per truck, and this in turn has made it necessary to employ trailers.

I have found that when trailers are employed, the power truck will also have to be loaded in order that the necessary traction shall be secured. The loading and unloading of the power truck consumes a lot of time that couldbe saved if the goods were all packed on the trailers, as in the latter case a trailer can be loaded with all the goods for a certain station and merely uncoupled andleft to be unloaded and loaded for the return trip, while the driver completes the trip and returns.

It is the object of this invention to provide means whereby suflicient traction may be secured to pull the trailers without the necessity of loading the truck, which therefore acts as a tractor. I accomplish the above object by means which I will now describe in detail, reference being had for the purpose to the accompanying drawing, in which Fig. 1 is a side elevation of a truck and trailer connected by my improved hitch; Fig. 2 is a plan view ef the parts shown in Fig. 1;

Fig. 3 is a diagram showing the manner in which the pulling force is resolved into various components;

Fig. 4 1s a diagram similar to that shown in Fig. 3, but showing the trailer on alower road level than the truck; and

Fig. 5 shows an elevation of one of the supporting brackets, part thereof being shown in section to better illustrate the construction.

The same reference numerals will be used to indicate the same parts throughout the several views. In the various figures I have shown a truck having the usual rear driving wheels 1, torque shaft 2, front wheels 3, radiator 4, hood 5, and chassis 6 which is supported on suitable springs 7 It is my intention to employ the truck as a tractor only and not to use it for carrying any load, the goodsto be transported being carried on trailers 8, one of which is shown in the drawing. In order to guide the trailer, I provide a tongue 9 which telescopes with a tubular member 10, the front end of which is secured to the rear of the truck chassis by suitable means such as a hook ll.

Members

9, 10 and 11 are not intended to be subjected to anytension, but to serve merely as a guiding means and as a means for backing and holding the trailer back on a down grade.

The trailer .is hitched to the tractor in the manner which I will now describe. On each side f the chassis I secure a bracket 12, having a pair of downwardly and outwardly extending legs 13 terminating in feet'l l, which are bolted to the chassis frame by means of bolts 15. The top of each bracket is provided with a bearing 16 which is constructed as shown in Fig. 5'. A

lower bearing member 17 rests upon a spring 18 and supports the end of a shaft 19, while the upper half 20 of the bearing is held rigidly in place b. means of bolts 21. The arrangement of t e bearing and cooperating parts is such that shaft 19 may move downwardly when the pressure thereon exceeds a certain limit.

In order to enable the truck to pull the trailer I secure the end of a cable 22 to a suitable bolt or ring 23 that is securely anchored to the truck chassis. The cable then passes over a pulley 24 which is slidably and rotatablymounted on shaft 19. The other end of cable 22 is secured to the trailer as indicated by numeral 25. The pulling oi the trailers is all accomplished by the cable 22, while the aiding is done by members ti. lid and lit. hen a turn is made pulley 24 will slide longitudinally on shaft 19 in the manner clearly a parent. lit has been custernary to depen entirely on means correspending to

members

9, 10 and 11 for pullin as well as for guiding the trailers, but it it found that in that case it was allways necessary to load the truck or tractor in order to secure the necessary traction; this entailed a lot of unnecessary work and consumed a lot' of valuable time. With my present hitch it is not necessary to carry any load on the tractor, as the pull 1n cable 22 produces a vertical force which acts as a load and provides the necessary pressure between the wheels and the road to secure the 4 M; traction.

11 order to describe my invention as clearly as possible. I have shown two diagrams (Figs. 3 and 4) which show graphicall the relationship of the various forces pro need. The pull of the tractor is indicated by the letter P, and for convenience sake I have taken the height of the brackets and the distance to the anchor 23 so that cable 22 makes an angle of 30 degrees with the chassis frame, and the distance to the trailer (Fig. 3) is such that the cable slants downwardl at a 30 degree angle. The relationship o the various forces is indicated on the several lines. The vertical component is shown as places on the road.

When the front end of the trailer drops into a hole in the road or to a lower level than the truck, the angle that the cable makes with the horizontal at the point of connection with the trailer'is increased, and

this increases the lifting power in proportion to the pull of the tractor.

it is evident from the above that by means of my improved hitch there will always be a downward pressure on the driving-wheels of the tractor which is proportional to the pull exerted by the tractor, and that therefore it is not necessary to load the tractor to secure the necessary traction.

Having now described my invention, what I claim is- 1. In combination, a tractor, a trailer. means for guiding the trailer in accordance with the movements of the tractor, and means connecting the trailer and tractor whereby the latter will pull the former, said means comprising a tension member having one end secured to the truck chassis, a bracket secured to the top of the chassis on each side thereof, a shaft connecting the upper portions of said brackets and lying substantially parallel to and vertically over the rear axle, a .pulley rotatably and slidably connected to said shaft, the tension member passing over said pulley and having its other end secured tot-he trailer. whereby the pulling force in said tension member will have a vertical component whose value varies directly with the force required to move the trailer.

2. In combination. a tractor, a trailer, means for guiding the trailer in accordance with the movements of the tractor, and means connecting the trailer and tractor whereby the latter will pull the former, said means comprisin a tension member having one end secure to the truck chassis, a bracket secured to the top of the chassis on each side thereof, a bearing in each bracket near the upper end thereof, said bearing having an upper stationary portion and a .ower movable portion, a spring upon which the lower bearing portion rests, a shaft mounted in said bearing, a pulley rotatably and slidably connected to said I shafit, the tension member passing over said pulley and having its other end secured to the trailer, whereby the pulling force in said tension member will have a vertical component whose value varies directly with the force required to move the trailer.

In testlmony whereof I aflix my signature.

JOHN H. KLEIN.